Simultaneous determination of levofloxacin, gatifloxacin and moxifloxacin in serum by liquid chromatography with column switching

Abstract

Liquid chromatography with a column-switching technique was developed for simultaneous direct quantification of levofloxacin, gatifloxacin and moxifloxacin in human serum. Serum samples were injected on a LiChroCART 4-4 pre-column (PC) filled with a LiChrospher 100 RP-18, 5 microm where fluoroquinolones (FQs) were purified and concentrated. The FQs were back-flushed from the PC and then separated on a Supelcosil ABZ+ Plus (150 mm x 4.6 mm i.d.) analytical column with a mobile phase containing 10 mM phosphate buffer (pH 2.5), acetonitrile (88:12, v/v) and 2mM tetrabutyl ammonium bromide. The effects of ion-pair reagents, buffer type, pH and acetonitrile concentrations in the mobile phase on the separation of the three FQs were investigated. Fluorescence detection provided sufficient sensitivity to achieve a quantification limit of 125 ng/ml for levofloxacin and moxifloxacin; 162.5 ng/ml for gatifloxacin with a 5 microl sample size. The on-line process of extraction avoids time-consuming treatment of the samples before injection and run time is shortened. The recovery, selectivity, linearity, precision and accuracy of the method are convenient for pharmacokinetic studies or routine assays.

CE‐ECL detection of gatifloxacin in biological fluid after clean‐up using SPE

“…For gatifloxacin, the LOQ and LOD were 5.0 Â 10 À8 and 2.0 Â 10 À8 g/mL at S/N of 10 and 3, respectively. This analysis system for gatifloxacin shows LOQ of 1-2 orders of magnitude lower than that of most of the previously reported chromatography-based method [4][5][6][7][8][10][11][12][13].…”

“…So far, some methods such as HPLC-UV [4][5][6][7], HPLCfluorimetry [6,8] [20] have been developed for the analysis of gatifloxacin in pharmaceutical preparation, biological fluid and animal tissue. Among these, HPLC [4,6,8,9] based strategies have been most universally used for the determination of this drug in biological samples since the complex matrix may severely interfere in the analysis if effective separation process is absent.…”

“…Among these, HPLC [4,6,8,9] based strategies have been most universally used for the determination of this drug in biological samples since the complex matrix may severely interfere in the analysis if effective separation process is absent. High separation efficiency, low sample amount required and short run time make CE a significant complement to HPLC for the detection of various drugs and metabolites in complex sample matrix.…”

“…So far, some methods such as HPLC-UV [4][5][6][7], HPLCfluorimetry [6,8], HPLC-MS [9], CE-UV [10][11][12], highperformance TLC [13], fluorimetry [14,15], UV [16], chemiluminescent analysis [17], voltammetry [18], polarography [19], atomic absorption spectrometry [20], conductometry [20] and colorimetry [20] have been developed for the analysis of gatifloxacin in pharmaceutical preparation, biological fluid and animal tissue. Among these, HPLC [4,6,8,9] based strategies have been most universally used for the determination of this drug in biological samples since the complex matrix may severely interfere in the analysis if effective separation process is absent.…”

“…This drug offers several advantages over previous antibiotics, including enhanced in vitro activity against clinically important pathogens and improved pharmacokinetics and pharmacodynamics characteristics, which may improve patient outcomes against certain bacterial pathogens, especially penicillin-resistant Streptococcus pneumoniae. The absolute bioavailability of gatifloxacin is 96%, with mean peak plasma concentration of 3.1-3.6 mg/mL usually occurring 1-2 h after the ingestion of a 400 mg therapeutic dosage [1][2][3].So far, some methods such as HPLC-UV [4][5][6][7], HPLCfluorimetry [6,8] [20] have been developed for the analysis of gatifloxacin in pharmaceutical preparation, biological fluid and animal tissue. Among these, HPLC [4,6,8,9] based strategies have been most universally used for the determination of this drug in biological samples since the complex matrix may severely interfere in the analysis if effective separation process is absent.…”